Enhancement in Thermal Properties of Organic Phase Change Material (Paraffin) via TiO2 Foam Doping

Abstract

Phase change materials (PCM) can absorb or release a huge amount of latent heat in accordance with the increase or decrease of the surrounding temperature. Among all the studied PCMs, organic PCM paraffin has been chosen due to the large energy storage capacity for thermal energy storage (TES). The present work introduces a thermally modified phase change material by TiO2 foam impregnation in paraffin. Three TiO2/paraffin PCM composites TPCM1, TPCM2, and TPCM3 containing 10 wt.%, 15 wt.%, and 20 wt.% of TiO2 foam with paraffin have been successfully synthesized for thermal energy storage. The porous TiO2 foam can provide a high paraffin loading capacity of up to 80 % (TPCM3) due to hollow cavities. TiO2 foam is uniformly distributed over the inner and outer surface of the paraffin as a nano additive to enhance the thermal conductivity (TC) of the composite PCM. The structural, morphological, and thermal study revealed that doping of the supporting material has potentially modified all the criteria of PCM composite for TES. The highest leakage-proof result was obtained for 20 wt.% of TiO2 foam impregnated composite (TPCM3) by analysing mass loss across 500 thermal cycles in an oven at 80°C. The thermal reliability of the TPCM3 composite has also been investigated after 500 thermal cycles. The TPCM3 composite maintains its crystalline nature with homogeneous dispersion and thermal stability without affecting the thermal and chemical properties of the PCM. The latent heat of the TPCM3 composite reached 182.87 J/g, and the thermal conductivity has been calculated at 0.71 W/m-K, which is 3.73 times higher than paraffin. The results concluded that synthesized TPCM3 composite could be a potential candidate for TES due to chemical and physical compatibility, easy synthesis process, good thermal and chemical reliability, and acceptable energy storage capacity with enhanced thermal conductivity.